Why you shouldn’t exercise to lose weight, explained with 60+ studies – Vox

“I’m going to make you work hard,” a blonde and perfectly muscled fitness instructor screamed at me in a recent spinning class, “so you can have that second drink at happy hour!”

At the end of the 45-minute workout, my body was dripping with sweat. I felt like I had worked really, really hard. And according to my bike, I had burned more than 700 calories. Surely I had earned an extra margarita.

The spinning instructor was echoing a message we’ve been getting for years: As long as you get on that bike or treadmill, you can keep indulging — and still lose weight. It’s been reinforced by fitness gurus, celebrities, food and beverage companies like PepsiCo and Coca-Cola, and even public-health officials, doctors, and the first lady of the United States. Countless gym memberships, fitness tracking devices, sports drinks, and workout videos have been sold on this promise.

There’s just one problem: This message is not only wrong, it’s leading us astray in our fight against obesity.

It’s interesting how wrong this thinking is, that exercise will make you lose weight. The multi-billion dollar diet industry is one of the biggest scams out there, constantly churning out new diet books, leading people to yo-yo as they lose weight, then gain it back.

One of the interesting points in the article is just how little of our caloric expenditure comes from activity.

There are three main components to energy expenditure, Kravitz explained: 1) basal metabolic rate, or the energy used for basic functioning when the body is at rest; 2) the energy used to break down food; and 3) the energy used in physical activity.

We have no control over our basal metabolic rate, but it’s our biggest energy hog. “It’s generally accepted that for most people, the basal metabolic rate accounts for 60 to 80 percent of total energy expenditure,” Kravitz said. Digesting food accounts for about 10 percent.

That leaves only 10 to 30 percent for physical activity, of which exercise is only a subset.

Exercise is certainly important; it has many health benefits. It just doesn’t help you lose much weight, in part because your body’s metabolism adjusts to your activity in order to maintain your weight.

I still wonder about the obesity epidemic. It’s not entirely about eating more; there aren’t that many people who necessarily started eating more and then became obese. Is obesity an inflammatory disease? Is our gut bacteria to blame? Is it caused by exposure to chemicals? I find that fact that obesity took off in the 1980s to be interesting, and wonder if it has something to do with environmental factors, such as new plastics that have been used since then, many of which are known to be endocrine disrupters.

Source: Why you shouldn’t exercise to lose weight, explained with 60+ studies – Vox

18 thoughts on “Why you shouldn’t exercise to lose weight, explained with 60+ studies – Vox

  1. “Exercise is certainly important; it has many health benefits. It just doesn’t help you lose weight”. This last statement is wrong, Kirk, and it is contradicted by the same article from which you quote it. Like most of the writing on health, diet, obesity, and exercise, this assertion isolates a single fact concerning one facet of a complex system, and draws global conclusions that are erroneous. Exercise not only helps you lose weight, it is absolutely critical for losing weight in a healthy manner. Among many other problems, if you lose weight without exercising, you will lose muscle and other tissue as fast or faster than you lose fat.

    It’s true that the article you reference contains a quote similar to your paraphrase, but it also contains the much more accurate and important statement, “Physical activity seems to set off a cascade of changes that can affect how much you eat, how many calories you use, and, in turn, your body weight.” Our knowledge of the weight and obesity questions is growing rapidly right now, and new information appears every few days. There is still much we don’t know.

    It’s wrong to downplay the multifactorial importance of exercise. It’s valuable for people to know that the number calories directly expended during exercise is less than most people think and hope, but the usefulness of that knowledge is undermined, if the focus isn’t widened to include all the less direct effects of exercise. It’s also misleading to discount the importance of the 20%-30% of daily calories expended by people who exercise actively. Would you trivialize the importance of a 20%-30% shift in your financial income? I doubt it, and you would be silly if you did. A similar variation in your nutrition and activity budget is very significant, even if it doesn’t dominate all other factors.

    • Yes and no. I’ve changed the text to say “lose much weight,” because, while it can help you lose a lot of weight if you exercise a lot, you’ll gain it back if you stop exercising. There was a recent article (in the NYT?) about people on some reality show who lost hundreds of pounds, and then gained it all back.

      The article says that 10-30% of calories burned is all your activity, not exercise. Part of that is what’s called non-exercise activity thermogenesis, or, simply, walking around and doing the stuff you do every day. So the total activity percentage is very small, compared to what people think. But, say you say, it’s important for people to know this. They problem is that they don’t know, and they may have devices that tell them how many calories they’ve expended, but those devices are not reliable.

      • OK, but the leadoff example in the article, which you start by quoting, is a person expending 700 calories in a 45-minute spinning class. If this person is consuming 2800 calories a day, which is above the USA average for active, healthy adult males, the spinning class alone is 25% of daily calories. If this person is a woman following the consumption averages, it’s closer to 35%. One of the flaws of the Vox article is that it constantly compares detailed specifics with vague averages. Sure there are people who expend less than 10% of their calories in exercise, but they aren’t the ones going to 45-minute spinning classes.

        Another problem with the article is that it almost exclusively cites very short-term studies, in one place calling 20 weeks “long-term”. It discounts the value of a moderate exercise program, that it says would “cause” a 200-pound man to lose five pounds in a month. That weight loss rate would bring the man down to 140 pounds in a year, which is significantly less than the ideal weight for the average adult male. Yet Vox dismisses it as useless.

        Obviously, weight loss and obesity are long-term problems, and no intervention has been shown to be the magic bullet for large groups of large people. To me, it’s irrelevant to say that exercise helps, but if you stop exercising, you gain it all back. If you stop exercising, every aspect of your health declines. Health maintenance is the longest term project in life, and every one of us can benefit from working on it.

        I agree that exercise alone does not have a great record for long-term weight loss, but calorie restriction alone has an even worse record. And while cheap exercise machines are poor at estimating calories burned, expensive ones are pretty accurate. Far more accurate that the calorie counting tables that people use to estimate their food consumption.

      • My understanding of the reason why it’s very easy to put weight back on is that fat cells have a lifespan of about 7 years. When you lose weight, you shrink the cells, but they’re still present, and it’s much easier for the body to fill them back up again than to create new fat cells. So if you work hard at losing weight for a year, but fail to keep the weight off for another six years, it will always be easy to regain it again.

        I think articles like this are counterproductive, because they imply (even when they explicitly say otherwise internally, as this one does) that exercise isn’t helpful. What they should say is that focusing on losing weight is a poor goal. You can be thin and desperately unhealthy. But if you eat well (which is more complex than whatever the fad diet of the week suggests) and exercise regularly in ways that promote cardiovascular health, muscle building, bone density, and flexibility (and improved mood and mental capacities will accompany that), you’re unlikely to be overweight too.

        • The problem is the prevailing attitude that says “if you are just more active you will lose weight.” That’s not going to happen, and it turns the issue of obesity into one of willpower, which is not necessarily the case.

          • I think people do believe that, but people believe a lot of wrongheaded things. That’s why I’m unimpressed with the article, because its entire focus, despite burying two paragraphs to the contrary in the middle, is that exercise is useless.

            A much more useful and powerful article would have been to point out that weight loss is only a small part of being healthier, and while exercise may not make a huge difference in weight in isolation, it is absolutely an essential aspect of health.

            But what do I know, I have only 26 years of experience being a publisher and 33 years of being a competitive runner. 🙂

  2. “Exercise is certainly important; it has many health benefits. It just doesn’t help you lose weight”. This last statement is wrong, Kirk, and it is contradicted by the same article from which you quote it. Like most of the writing on health, diet, obesity, and exercise, this assertion isolates a single fact concerning one facet of a complex system, and draws global conclusions that are erroneous. Exercise not only helps you lose weight, it is absolutely critical for losing weight in a healthy manner. Among many other problems, if you lose weight without exercising, you will lose muscle and other tissue as fast or faster than you lose fat.

    It’s true that the article you reference contains a quote similar to your paraphrase, but it also contains the much more accurate and important statement, “Physical activity seems to set off a cascade of changes that can affect how much you eat, how many calories you use, and, in turn, your body weight.” Our knowledge of the weight and obesity questions is growing rapidly right now, and new information appears every few days. There is still much we don’t know.

    It’s wrong to downplay the multifactorial importance of exercise. It’s valuable for people to know that the number calories directly expended during exercise is less than most people think and hope, but the usefulness of that knowledge is undermined, if the focus isn’t widened to include all the less direct effects of exercise. It’s also misleading to discount the importance of the 20%-30% of daily calories expended by people who exercise actively. Would you trivialize the importance of a 20%-30% shift in your financial income? I doubt it, and you would be silly if you did. A similar variation in your nutrition and activity budget is very significant, even if it doesn’t dominate all other factors.

    • Yes and no. I’ve changed the text to say “lose much weight,” because, while it can help you lose a lot of weight if you exercise a lot, you’ll gain it back if you stop exercising. There was a recent article (in the NYT?) about people on some reality show who lost hundreds of pounds, and then gained it all back.

      The article says that 10-30% of calories burned is all your activity, not exercise. Part of that is what’s called non-exercise activity thermogenesis, or, simply, walking around and doing the stuff you do every day. So the total activity percentage is very small, compared to what people think. But, say you say, it’s important for people to know this. They problem is that they don’t know, and they may have devices that tell them how many calories they’ve expended, but those devices are not reliable.

      • OK, but the leadoff example in the article, which you start by quoting, is a person expending 700 calories in a 45-minute spinning class. If this person is consuming 2800 calories a day, which is above the USA average for active, healthy adult males, the spinning class alone is 25% of daily calories. If this person is a woman following the consumption averages, it’s closer to 35%. One of the flaws of the Vox article is that it constantly compares detailed specifics with vague averages. Sure there are people who expend less than 10% of their calories in exercise, but they aren’t the ones going to 45-minute spinning classes.

        Another problem with the article is that it almost exclusively cites very short-term studies, in one place calling 20 weeks “long-term”. It discounts the value of a moderate exercise program, that it says would “cause” a 200-pound man to lose five pounds in a month. That weight loss rate would bring the man down to 140 pounds in a year, which is significantly less than the ideal weight for the average adult male. Yet Vox dismisses it as useless.

        Obviously, weight loss and obesity are long-term problems, and no intervention has been shown to be the magic bullet for large groups of large people. To me, it’s irrelevant to say that exercise helps, but if you stop exercising, you gain it all back. If you stop exercising, every aspect of your health declines. Health maintenance is the longest term project in life, and every one of us can benefit from working on it.

        I agree that exercise alone does not have a great record for long-term weight loss, but calorie restriction alone has an even worse record. And while cheap exercise machines are poor at estimating calories burned, expensive ones are pretty accurate. Far more accurate that the calorie counting tables that people use to estimate their food consumption.

      • My understanding of the reason why it’s very easy to put weight back on is that fat cells have a lifespan of about 7 years. When you lose weight, you shrink the cells, but they’re still present, and it’s much easier for the body to fill them back up again than to create new fat cells. So if you work hard at losing weight for a year, but fail to keep the weight off for another six years, it will always be easy to regain it again.

        I think articles like this are counterproductive, because they imply (even when they explicitly say otherwise internally, as this one does) that exercise isn’t helpful. What they should say is that focusing on losing weight is a poor goal. You can be thin and desperately unhealthy. But if you eat well (which is more complex than whatever the fad diet of the week suggests) and exercise regularly in ways that promote cardiovascular health, muscle building, bone density, and flexibility (and improved mood and mental capacities will accompany that), you’re unlikely to be overweight too.

        • The problem is the prevailing attitude that says “if you are just more active you will lose weight.” That’s not going to happen, and it turns the issue of obesity into one of willpower, which is not necessarily the case.

          • I think people do believe that, but people believe a lot of wrongheaded things. That’s why I’m unimpressed with the article, because its entire focus, despite burying two paragraphs to the contrary in the middle, is that exercise is useless.

            A much more useful and powerful article would have been to point out that weight loss is only a small part of being healthier, and while exercise may not make a huge difference in weight in isolation, it is absolutely an essential aspect of health.

            But what do I know, I have only 26 years of experience being a publisher and 33 years of being a competitive runner. 🙂

  3. It is difficult to adequately describe how fundamental exercise is! I know what you are saying, Kirk. I believe exercise is absolutely fundamental, and my goal is to do it every single day, and there is also truth to your observations. Here are a couple of my own observations over the past 9 years:

    1. It is true : if you exercise specifically to lose weight only, that is not a sustaining reason. The reason I try to exercise everyday is to live a healthy life. Losing weight, and being healthy, are not the same thing. But my argument is that exercise is fundamentally important to good health, and that alone is the reason to exercise. This is the sustaining reason to exercise, and the key word is “sustain”. The folks in that tv show are unlikely to keep exercising because they were doing it for the wrong reason. It sounds trivial, but it is not – exercise because you want to be healthy in your life, not because you want to lose weight.

    2. Your body reflects your lifestyle. A “lifestyle” is what you do over time. A person with a healthy lifestyle will have a body that reflects the lifestyle. The key is that, over time, your body will reflect that lifestyle, period. The notion of gaining or losing weight loses relevance in this perspective, because “weight at a particular point in time” is no longer relevant – what is relevant is what you do day in and day out, and we DO know what makes us healthy in general. In this context, a lot more goes into health than any number on the scale.

    I very much enjoy and learn from your articles on music, iTunes, etc. They are incredibly helpful! Thanks for all your good work.

    Paul Núñez

    • I totally agree. But what the article points out is the fallacy that assumes that we will lose weight if we are just a bit more active.

  4. It is difficult to adequately describe how fundamental exercise is! I know what you are saying, Kirk. I believe exercise is absolutely fundamental, and my goal is to do it every single day, and there is also truth to your observations. Here are a couple of my own observations over the past 9 years:

    1. It is true : if you exercise specifically to lose weight only, that is not a sustaining reason. The reason I try to exercise everyday is to live a healthy life. Losing weight, and being healthy, are not the same thing. But my argument is that exercise is fundamentally important to good health, and that alone is the reason to exercise. This is the sustaining reason to exercise, and the key word is “sustain”. The folks in that tv show are unlikely to keep exercising because they were doing it for the wrong reason. It sounds trivial, but it is not – exercise because you want to be healthy in your life, not because you want to lose weight.

    2. Your body reflects your lifestyle. A “lifestyle” is what you do over time. A person with a healthy lifestyle will have a body that reflects the lifestyle. The key is that, over time, your body will reflect that lifestyle, period. The notion of gaining or losing weight loses relevance in this perspective, because “weight at a particular point in time” is no longer relevant – what is relevant is what you do day in and day out, and we DO know what makes us healthy in general. In this context, a lot more goes into health than any number on the scale.

    I very much enjoy and learn from your articles on music, iTunes, etc. They are incredibly helpful! Thanks for all your good work.

    Paul Núñez

    • I totally agree. But what the article points out is the fallacy that assumes that we will lose weight if we are just a bit more active.

  5. Good article, though I disagree with some things in it, such as the plug for low fat diets. Exercise is certainly useful, even if only for staying strong and flexible enough to avoid falls as you get older (broken hips tend to be fatal within a year), but one of exercises strongest side effects is that it makes you hungry. Carbohydrates also make you hungry, because they raise insulin levels. On the other hand, a side effect of losing weight is often to spontaneously start doing more, because it becomes easier.

    So many people look for a single solution (to pretty much everything), but there isn’t one. There’s a large number of things that influence weight, from genetics to many environmental factors, to viruses. But the biggest correlation for the ‘epidemic’ is pretty clearly the replacement of fat in the diet with processed carbohydrates. As people in the west started eating very low fat diets–and getting more exercise–in the 80s, the obesity rate soared.

    Not everyone who tries low carb loses a lot of weight though. There could other influences that affect them more, or perhaps not all of the bad effects of decades of excess carbs and high insulin levels are reversible.

    Traube’s “Good Calorie, Bad Calorie” is a great (though long) introduction to the physiology involved, as well as the history and politics. He includes a vast number of references to everything. A few sound bites:

    * Modern nutrition ‘science’ is more religion than science. It pays no attention to actual physiology research, of which there is a lot (though never enough).

    * In women, there is zero correlation between eating saturated fats with heart disease of any kind. In men, there is a tiny correlation because about 10% of men have a genetic issue with how a particular lipoprotein behaves. There is a strong correlation between eating a lot of fat and losing weight (or not gaining it in the first place).

    * Low cholesterol blood levels correlate strongly with shorter lifespan, but poorly with heart disease. It’s partly a trade off between heart disease and cancer.

    * All flours, whether whole grain or not, raise insulin as much and as fast as straight glucose. Insulin is Bad Stuff in many ways, one of which is to prevent cells from using fats as fuel. It’s the only major hormone that does that. Fats are a cleaner burning fuel than carbs, and produce many fewer of the potentially cancer causing free radicals that require antioxidants to combat.

    You don’t necessarily have to go full Atkins. Start with ditching sugar water (including fruit juice and artificial sweeteners, which in some people can provoke as strong an insulin reaction as sugar). If that’s not enough, ditch all sugars (including fruit), then anything made with flour, then starchy vegetables such as potatoes. Odds are that at some point, you’ll not only lose weight, but gain strength because of better nutrition, and start getting more exercise because your body demands it.

  6. Good article, though I disagree with some things in it, such as the plug for low fat diets. Exercise is certainly useful, even if only for staying strong and flexible enough to avoid falls as you get older (broken hips tend to be fatal within a year), but one of exercises strongest side effects is that it makes you hungry. Carbohydrates also make you hungry, because they raise insulin levels. On the other hand, a side effect of losing weight is often to spontaneously start doing more, because it becomes easier.

    So many people look for a single solution (to pretty much everything), but there isn’t one. There’s a large number of things that influence weight, from genetics to many environmental factors, to viruses. But the biggest correlation for the ‘epidemic’ is pretty clearly the replacement of fat in the diet with processed carbohydrates. As people in the west started eating very low fat diets–and getting more exercise–in the 80s, the obesity rate soared.

    Not everyone who tries low carb loses a lot of weight though. There could other influences that affect them more, or perhaps not all of the bad effects of decades of excess carbs and high insulin levels are reversible.

    Traube’s “Good Calorie, Bad Calorie” is a great (though long) introduction to the physiology involved, as well as the history and politics. He includes a vast number of references to everything. A few sound bites:

    * Modern nutrition ‘science’ is more religion than science. It pays no attention to actual physiology research, of which there is a lot (though never enough).

    * In women, there is zero correlation between eating saturated fats with heart disease of any kind. In men, there is a tiny correlation because about 10% of men have a genetic issue with how a particular lipoprotein behaves. There is a strong correlation between eating a lot of fat and losing weight (or not gaining it in the first place).

    * Low cholesterol blood levels correlate strongly with shorter lifespan, but poorly with heart disease. It’s partly a trade off between heart disease and cancer.

    * All flours, whether whole grain or not, raise insulin as much and as fast as straight glucose. Insulin is Bad Stuff in many ways, one of which is to prevent cells from using fats as fuel. It’s the only major hormone that does that. Fats are a cleaner burning fuel than carbs, and produce many fewer of the potentially cancer causing free radicals that require antioxidants to combat.

    You don’t necessarily have to go full Atkins. Start with ditching sugar water (including fruit juice and artificial sweeteners, which in some people can provoke as strong an insulin reaction as sugar). If that’s not enough, ditch all sugars (including fruit), then anything made with flour, then starchy vegetables such as potatoes. Odds are that at some point, you’ll not only lose weight, but gain strength because of better nutrition, and start getting more exercise because your body demands it.

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